R&D Report 1995-10 : A method for the calculation of tolerances for display primary chromaticity coordinates. A. Roberts The manufacturers of displays for television and other visual display systems are rarely given sufficient information to ensure that their products perform satisfactorily. Typically, parameters such as the peak brightness and primary chromaticities, transfer characteristic and illumination uniformity are supplied, but this information is usually generic, it does not refer specifically to the display in question. There is no internationally accepted method for defining the tolerances of primaries. A study was made of the tolerance zones for the EBU primaries, with the aim of developing a strategy which might work successfully on other standards. As a result of this study, a method has been developed, and a proposal made for tolerance zones for the primaries specified in ITU-R Recommendation BT.709.